Approach

The overall goal of treatment is to manage wounds properly in order to prevent morbidity and mortality; this includes prevention and/or treatment of infectious complications. Animal scratches such as superficial tooth scratches should be treated as bite wounds, as they are often contaminated with saliva. However, common superficial claw scratches, such as cat scratches, do not require bite wound treatment.

Wound care

All animal bites should be considered contaminated and require wound care. The affected skin surface should be cleaned and the unclosed wound copiously irrigated with water, normal saline, or lactated Ringer's solution under high pressure (with an 18- or 19-gauge needle or catheter tip and large syringe).[39][40] Irrigation with a dilute povidone-iodine solution may also be considered, particularly if the animal is believed to be rabid.[31][41] Devitalised or necrotic tissue should be debrided and abscesses drained.

Clenched fist injuries require special consideration. A hand specialist should evaluate these injuries for penetration into the synovium, joint capsule, and bone. These wounds may extend deeply and carry organisms in the deep compartments and potential spaces of the hand. Antibiotic prophylaxis is recommended in all cases.[42]

Wound closure and repair

Wound closure is a controversial issue. There is general agreement that infected wounds and those seen >24 hours after the bite should be left open. Some physicians recommend consideration of wound closure after irrigation and debridement in patients presenting <8 hours after the injury, if there is no visible evidence of infection.

Wounds with a high risk of complication or infection, such as limb wounds, should be left open. In wounds where there are significant cosmetic concerns, such as facial wounds, primary closure is often undertaken by a plastic surgeon or other expert.[43][44][45][46]​ The decision around primary wound closure weighs function and cosmesis against infection, and should be shared between clinician and patient.[10] One 2019 Cochrane systematic review on dog bites found no indication that primary closure reduces infection rates or has an impact on cosmesis, based on weak evidence.[10][47]​​[Figure caption and citation for the preceding image starts]: Top: breakdown of a leg bite wound and infection seven days after it was sutured in primary care. Bottom: resultant scarring 18 months laterMorgan M, Palmer J. BMJ 2007;334:413 doi:10.1136/bmj.39105.659919.BE [Citation ends].com.bmj.content.model.Caption@7f467fd6

If wounds are complicated by fractures, communication into the joint space, loss of a significant amount of tissue, disruption of deep anatomical structures, or are serious hand or cranial bites, then orthopaedic or surgical consultation is required.

Prophylactic antibiotics for uninfected bite wounds

The indications for antibiotics as prophylaxis are unclear, and their effectiveness is uncertain.[10][48][49][50][51][52]​​

Prophylactic (also known as pre-emptive) antibiotics are recommended in all cases of clenched fist injury and should be considered in patients with factors that increase the likelihood of infection, or have serious implications of infection.[42]

Wound factors include:[14][31]​​[42][53]

  • Bites to the hand, head, neck, or genital region

  • Puncture or crush wounds

  • Deep structure involvement or requiring surgical repair

  • Bite or laceration from a human or cat that results in broken skin

  • Wounds over or near bone, tendons, ligaments, or joints

  • Limbs with impaired vasculature or lymphatic return.

Patient factors include:[14][31]​​[42][53]

  • Previous medical procedures, for example, splenectomy or lymph node removal

  • Underlying medical conditions, for example, advanced liver disease, diabetes mellitus, or other immunosuppressive conditions.

For a single, uninfected animal bite to a person with no penicillin allergy, treatment with agents that cover both aerobic and anaerobic bacteria (e.g., a beta-lactam, or a second- or third- generation cephalosporin plus clindamycin or metronidazole) may be considered.[42][53]​​ With penicillin allergy, treatment with a combination of agents, including clindamycin or metronidazole plus a sulfonamide (e.g., trimethoprim/sulfamethoxazole) or a fluoroquinolone (e.g., ciprofloxacin, levofloxacin), is an alternative option.[42] The combination of doxycycline plus metronidazole may also be considered.[53][54]​​ Moxifloxacin has good anaerobic cover and may be considered as a single agent in patients with penicillin allergy.[42] For pregnant women, azithromycin and metronidazole is an option. Always seek consultant advice before prescribing.[55]

In general, prophylactic therapy is given for 3 to 5 days.[42]​ It is recommended that local guidance for antimicrobial therapy is used where available.

Treatment of infected single bite wounds

Antibiotic therapy is indicated in patients with overt signs of infection. People with a single, uncomplicated, infected bite with the infecting organism unknown, and who are not allergic to penicillin, should be treated with agents that cover both aerobic and anaerobic bacteria (e.g., a beta-lactam, or a second- or third-generation cephalosporin plus clindamycin or metronidazole).[42][53] Those who are penicillin-allergic should receive a combination of agents, including clindamycin or metronidazole plus a sulfonamide (e.g., trimethoprim/sulfamethoxazole) or a fluoroquinolone (e.g., ciprofloxacin, levofloxacin).[42] The combination of doxycycline plus metronidazole is also an option.[53][54] Moxifloxacin has good anaerobic cover and can be used as a single agent in patients with penicillin allergy.[42]

No standard guidelines exist for length of therapy, but treatment of established uncomplicated infection is usually 10 to 14 days.[14]

Treatment of complicated bites

Hospital admission for parenteral therapy should be considered for patients with:

  • Multiple or severe bites

  • Severe local infection

  • Evidence of systemic infection

  • Joint or bone involvement

  • Severe underlying illnesses or immunocompromising conditions.

No standard guidelines exist for length of therapy, but treatment of 10 to 14 days of therapy is recommended for localised infection (e.g., cellulitis, skin abscess), whereas complex infections (including osteomyelitis) may need to continue for 4 to 6 weeks.[14]

Post-exposure prophylaxis

Post-exposure prophylaxis (PEP) for transmissible diseases, especially rabies and tetanus, should be considered.[38][56]​​ See Rabies and Tetanus.

Notification of public health/law enforcement

Local law enforcement and/or public health departments may need to be contacted about a bite injury. Local practices and regulations vary.[18][38]​ These agencies may be helpful in animal bite investigation, post-bite rabies quarantines, identification and regulation of feral animals, and public health reporting.​

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